TORPIDITY. 79 



insects are in the dog-days." Thus do the comforts of a 

 warm hearth afford the cricket a safe refuge, not from 

 death, but from temporary toi-pidity ; which it can support 

 for a long time, when deprived by accident of artificial 

 warmth. " I came to the knowledge of this fact," he says, 

 " by planting a colony of these insects in a kitchen, where 

 a constant fire is kept through the summer, but which is 

 discontinued from November to June, with the exception 

 of a day, once in six or eight weeks. The crickets were 

 brought from a distance, and let go in this room in the be- 

 ginning of September 1806 : here they increased consi- 

 derably in the course of two months, but were not heard 

 or seen after the fire was removed. Their disappearance 

 led me to conclude that the cold had killed them : but in 

 this I was mistaken ; for, a brisk fire being kept up for a 

 whole day in the winter, the warmth of it invited my 

 colony from their hiding-place, but not before the evening, 

 after which they continued to skip about and chirp the 

 greater part of the following day, when they again disap- 

 peared ; being compelled by the returning cold to take re- 

 fuge in their former retreats. They left the chimney-cor- 

 ner on the 28th of IMay 1807, after a fit of very hot wea^ 

 ther, and revisited their winter residence on the 31st of 

 August. Here they spent the summer merely, and lie 

 torpid at present (Jan. 1808), in the crevices of the chim- 

 ney, with the exception of those days on which they are 

 recalled to a temporary existence by the comforts of a fire." 

 Nothing is known with regard to the hybernation of the 

 intestinal worms. Those which inhabit the bodies of tor- 

 pid quadrupeds, in all probability, like these, experience a 

 winter lethargy. If they remain active, they must possess 

 the faculty of resisting great alterations of temperature. 

 Among the infusory animals, numeious instances of sus- 



